This invention relates to an integrated circuit, and electronic equipment and an assembly method which uses suitable integrated circuits when preparing many kinds of electronic equipment having varieties of functions from an upper rank to a lower rank function respectively, according to demand.
The electronic equipment includes a magnetic recording and regenerative unit, video recorder/player, video-cassette recorder and the like. In this case, the additional functions to the magnetic recording and regenerative units include, for example, an on-screen display (OSD), PAL system applicable to a plurality of different languages, HiFi, and two-head system or four-head system having a specification of HiFi or NTSC/PAL regenerative system.
The conventional technologies are explained in an example for the magnetic record and/or the generative apparatus or video tape recorder (hereinafter called "VTR"). The basic structure of this VTR is shown by big block view in FIG. 1.
In FIG. 1, 101 is a TV signal processing portion which processes signals from a tuning circuit 102 of the TV signal, 103 is a video signal processing portion which outputs TV signals being output from said TV signal processing portion to a recording and/or generative circuit 104 where signal recording and generation thereof are performed in conjunction with a magnetic tape and rotary magnetic heads 105 having two-head system or four-head system, and 113 is an antenna terminal.
Number 106 is a timer portion which counts time for a reservation of TV program and for present time, 107 is a key interface portion which inputs a signal from the key input portion 108, 109 is a driver portion which controls an indication to a fluorescent indicating tube 110, and 111 is a driving control portion which outputs the control signal to the driving mechanism 113 which controls magnetic head 105 and capstan 112 for a servo control (speed control, phase control).
A system control portion 120 controls the whole VTR with input and output signals through connections to the tuning circuit 102, timer portion 106, magnetic signal processing portion 103, key interface portion 107, fluorescent indication tube driver portion 109, and the driving control portion 111, respectively.
Formerly, in the VTR described above, the timer portion 106, fluorescent indicator tube driver portion 109, and the system control portion 120 are stored in an integrated circuit 121. On the other hand, the drive control portion 111 is structured to an exclusive integrated circuit called a "digital servo integrated circuit" (this structure is hereinafter called "system 1"). However, in the case of a four-headed system, special regeneration (especially slow regeneration) cannot be smoothly operated in this structure, and a special regenerative integrated circuit or an expensive servo integrated circuit having such function must be additionally used. Thus, in the above structure system 1, when the four-headed system is used, the following two structures are widely used:
a structure wherein the system control portion 120 and the driving control portion 111 are stored in an integrated circuit 122, while the timer portion 106 and the fluorescent indicating tube driver portion 109 are stored in another integrated circuit 123 (this structure is hereinafter called "system 2"); or a structure wherein the system control portion 120, driving control portion 111 and the timer portion 106 are stored in an integral circuit 124, and the fluorescent indicating driver portion 109 is used as an exclusive integrated circuit (this structure is hereinafter called "system 3"). PA1 1. To make the package shape (number of pins) in the integrated circuit for electronic equipment system control in common use; PA1 2. To select and use one of said integrated circuit groups having a necessary and the minimum suitable ROM capacity corresponding to each of a plurality of functional additions; PA1 3. To decrease the manufacturing cost of the equipment by restricting large-scale integrated circuits to be used to only one; and PA1 4. To decrease the cost of the assembly step by making the main printed circuit board commonly useful and making the inserting positions of the electronic parts to be mounted to the same position; and PA1 said memory circuit memorizes a program which practices a software function of said electronic equipment, and forms one of a series of integrated circuit groups which has an interchangeability with respect to said lower rank function by incorporating a one memory circuit having each function from a software of a higher rank to a software of a lower rank respectively; each memory capacity of said series of integrated circuit group has a fixed amount which lessens corresponding to each one from said software of upper rank function to lower rank function respectively; the arranged position and size of each outer input-output lead wire of said series of the integrated circuit group are partially or totally the same as those of the lead wire of the integrated circuit of upper rank function; and said signal which inputs or outputs said lead wire has an interchangeability with respect to the integrated circuit to the lower rank function. PA1 a step of selecting at least one integrated circuit corresponding to a kind of an equipment to be produced and functions to be added from said series of integrated circuit group; PA1 a step of inserting said selected integrated circuit to said main printed circuit board; and PA1 a step of mounting said electronic parts only onto said coordinated positions corresponding to said kind of equipment to be produced and function to be added on said main printed circuit board are carried out in this order. PA1 said selected integrated circuit is provided with a digital circuit integrating the system control portion of said total recorder and/or regeneration unit, timer portion and indication tube control drive portion, and PA1 a memory circuit having a software function of the program data by which two heads or four heads and the servo control of the head and capstan portion corresponding to the specification of plurality of added functions regarding the heads; PA1 the assigned position and size of the input and output lead wire of said integrated circuit group and input and output signal thereof have an interchangeability to the lower rank function, respectively; and PA1 the main printed circuit board incorporating said integrated circuit carries a commonly usable wiring pattern for any integrated circuit from said upper rank function to the lower rank function.
At present, various kinds of VTRs are manufactured and distributed according to user's requests, e.g., even in the VTR of the NTSC system in Japan and the U.S., there exist 2-headed and four-headed systems, and those two systems have further functional additions (e.g., OSD, HiFi, etc.). Such production of various types in small amounts impedes cost reductions. To overcome this, even when many kinds of VTRs having different functional additions are made, common use of parts incorporated into an inner portion and the preparation step are performed. Particularly, when the layout of the circuit boards is made in common, since the common parts are assigned at the same position on the circuit board, an automatic insertion of parts is available by using an automatic inserter, or manual insertion by hand becomes easy, thereby increasing productivity. In other words, in the case of automatic insertion, if the positions of commonly usable parts thereof are memorized, then its insertion can be performed by correction or addition of each memory provided at a certain part according to each kind without any memory of inserting position from first. In addition, in the case of manual insertion, the generation of insertion errors by the operator decreases because the insertion position is the same with respect to the part.
However, when this common usage of parts is enlarged to integral circuits, among the VTR of two- and four-headed systems having various kinds of functional additions, the specification of said integrated circuit is set so that the highest rank function VTR having the largest number of functional additions may operate, then said integrated circuit is allowed to keep the interchangeability to the lower rank function, and accordingly, the VTR in which said integrated circuit is incorporated, includes unused functions.
Accordingly, in order to decrease manufacturing cost, VTRs of a two-head system are made to be common in circuit board and parts by using the structure of system 1, while VTRs of a four-head system are made to be common in circuit board and parts by using the structure of system 2 or 3.
As is illustrated in systems 1, 2 and 3, at least two large-scale integrated circuits were used as its main structures, resulting in increased costs.
Further, as the system control portion and the fluorescence indicating tube driver portion, or the system control portion and the driving control portion were provided in separate large-scale integrated circuits, both integrated circuits were connected with copper foil wires on the circuit board. Accordingly, noises from other devices provided both inside and outside the unit, overlap at the copper foil wires through which the control signal is sent, and cause mistakes in operation. In addition, when the package shape of said integrated circuit (including number of pin) becomes a plurality, the manufacturing step of the integrated circuit and its examination are performed at different organizations, and the results of the examination become different. Accordingly, the simplification of the manufacturing steps of the integrated circuit becomes difficult, and the decrease in cost of the integrated circuit body is also difficult.
On the other hand, if a single integrated circuit is used, the memory circuit (such as ROM, etc.) for software mounted on said integrated circuit requires a great memory capacity for keeping the highest function. Accordingly, the VTR products which use only the lowest function carry unnecessary and expensive memory and no meaning to use a single integrated circuit can be found.
This invention solves such problems and its objects include the following:
to eliminate the wiring between circuit boards by storing the system control portion and a driven control portion to said one integrated circuit by an effect of one main printed board and to prevent operational errors due to the overlapping of noises.